JPS58124145A - Controlling apparatus of hot water storage type electric water heater - Google Patents

Abstract

PURPOSE:To reduce the heat loss generated within the duration from the time of heating-up to the time of service by a method wherein the required hour to energize to a heating element is calculated based upon the heat quantity of remaining hot water and the energizing is started at such a certain time as to heat up the water in a hot water storage tank simultaneously with the time of expiration of midnight power supply time. CONSTITUTION:A heater 3 and a temperature detector 12 are provided at the lower part of the hot water storage tank 11 and a communicating pipe 17 communicates the lower part of the hot water storage tank 11 to a hot water supply pipe 14 and provided with a circulating pump 16 in itself. Let Vl be the total volume of the hot water storage tank 11 filled full of hot water having the temperature of T1 deg.C. When V1l of the hot water is consumed, V2l of the hot water with the temperature of T1 deg.C is left behind and, after that, V1l of the water with the temperature of t deg.C is added to the hot water storage tank 11. At this moment, the water in the hot water storage tank 11 is agitated by operating the pump 16 to uniformize the temperatures of the water to turn to be T2 deg.C. Under the condition as described above, the heat quantity C kcal of remaining hot water, the heat quantity Cin kcal to be added to the water in the hot water storage tank 11 to rise to the required boiling-up temperature of T deg.C and the required energizing hour Hhr are obtained from the relationships as follows: C=V(T2-t), Cin= V(T-t)-C, H=Cin/(860.W) where W is the rated consumption electric energy of the heating element. Accordingly, the energizing is started Hhr before the time of the end of midnight power supply.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a control device for a hot water storage type electric water heater that uses late-night electricity, and calculates the required energization time to the heating element from the amount of heat held by the remaining hot water in the hot water storage tank. The purpose is to reduce heat loss after boiling by starting energizing the heating element in the middle of the late-night energization period so that the boiling occurs at the same time as the end of the energization period of the late-night electricity.

The main power supply circuit of a hot water storage type electric water heater that uses conventional late-night electricity #! It is shown in Figure 11. In the figure, 1 is the power supply, 2 is the time switch for late-night power, and the power is generally on during the 23-hour period.
to 7 a.m. the next morning.

Reference numeral 3 denotes a heating element, and the capacity of the heating element is set in advance so as to boil water at around 8°C, which corresponds to the winter water temperature, to 85°C during the late-night power supply time. 4 is an automatic temperature regulator, which has a normally closed contact and opens when the temperature of the hot water in the hot water storage tank reaches 85°C.

Next, the function and operation will be explained. When the midnight power supply start time arrives, the contact of the time switch 2 is closed and the supply of electricity to the heating element 3 is started. When the temperature of the hot water in the hot water storage tank reaches 85° C., the contacts of the automatic temperature controller 4 are opened and the electricity to the heating element 3 is stopped.

In this way, the entire amount of stored hot water is boiled to 85 degrees Celsius every morning.

However, the amount of hot water used is not always the same, and you may end up leaving behind a daily bath.

Therefore, if there is residual hot water, it will boil up and cool down in a short period of time, and the power load will be concentrated immediately after electricity starts, making it impossible to equalize the power load, which is the original purpose of late-night power, and resulting in poor power transmission efficiency. (At the same time, the hot water heated up in the hot water storage tank was left unused for a long time, resulting in increased heat loss due to natural heat dissipation.)

In addition, conventional hot water storage type electric water heaters are not equipped with a device for detecting the amount of heat of remaining hot water, and only some devices have been used to detect the amount of remaining hot water. Detecting the amount of remaining hot water was also a step-by-step measurement in which multiple temperature sensors, such as thermostats and thermistors, were placed on the outside wall of the hot water storage tank to detect temperature changes at those locations. Because of this, I didn't have the remaining heat the next time.

The present invention attempts to solve these drawbacks by detecting the amount of heat remaining in the hot water storage tank and transferring it to the heating element.

In FIG. 2, 11 is a hot water storage tank, 12 is a temperature detector installed at the bottom of the hot water storage tank 11 to measure the temperature of hot water in the hot water storage tank 11, 13 is a water supply pipe, 14 is a hot water supply pipe, 15
is a faucet installed at the tip of this water supply pipe. 16 is a circulation pump, and 1! is located at the bottom of the hot water storage tank 11 at one end. It is provided in the middle of a communication pipe 17 whose end is connected to the middle of the hot water supply pipe 14, and water is routed from the lower part of the hot water storage tank 11 to the connection part with the hot water supply pipe 14 via the communication pipe 17. In FIG. 3, 20 is a residual water heat amount detection means described below, 21 is a calculation means A for calculating the amount of heat to be heated from the heat amount detected by the residual water amount detection means 20, and 22 is the amount of heat determined by the calculation step A21. The calculation means B, 23 that calculates the required energization time for the heating element 3 from the amount of heat to be heated is operated by the calculation means B22 at the midnight energization end time.
This is a timer device for starting energization of the heating element 3 in the middle of the late-night power energization time period so as to obtain the predetermined energization time determined in .

Next, a method of detecting the amount of heat of the remaining water by the remaining water heat amount detection means 20 will be explained with reference to FIGS. 4 and 5.

As shown in FIG. 2, it is assumed that the hot water storage tank 11 is initially filled with hot water at T3°C.

FIG. 4 shows the temperature distribution inside the hot water storage tank 11 after using hot water V, (1) from the faucet 15 in this state. That is, t ("C) water flows into the lower part 11a of the hot water storage tank from the water supply pipe 13 by the amount of hot water used, V, [1), and v2 of hot water T, ("C) flows into the upper part 11b of the hot water storage tank.
[Also] it remains. In this state, when the circulation pump 16 is operated with the faucet 15 closed, the lower part of the hot water storage tank 11
Since water b flows from the upper part 11b of the hot water storage tank through the communication pipe 17 and disturbs the hot water tank in the upper part 11b of the hot water storage tank,
The water temperature gradually becomes average.

FIG. 5 shows the temperature distribution of the hot water storage tank 11 where the hot water temperature has been averaged in this way, and the average temperature is T2 ("C).

Next, we will explain how to calculate the residual heat amount. The total amount of the hot water storage tank 11 is ct] (II value v=v, +V2), then the temperature measured before the operation of the circulation pump 16 by the temperature detector 12 installed at the lower part 11d of the hot water storage tank is t ('C), and the temperature of the circulation pump is t ('C). Since the measured temperature after 16 runs is T2 ("C), the remaining hot water heat amount C (kcal) can be calculated as follows.

C =V C1nCkcal] is Cin = V (T - t) - C(kcal
) can be found. Further, the calculation means B22 calculates the required energization time from the value of the heat amount Cin to be heated, and calculates the rated power consumption of the heating element 3 as W [ku+/hr].
Then, the required energization time H is determined by H=-needle2-('nr)vJλ3O. Then, the timer device 23 controls the heating element 3 from the middle of the energization period of the late-night power so that the required energization time determined by the calculating means B22 is obtained at the end time of the energization of the late-night power.
Start energizing.

As described above, the present invention calculates the amount of heat to be heated by detecting the amount of remaining hot water, further calculates the required energization time to the heating element from this amount of heat, and sets the energization time to the time period when the late-night power is on. Since the system is designed to extinguish the fire at the end of the fire, the time the boiled hot water is left unused is shortened, and heat loss due to natural heat radiation from the hot water storage tank is reduced, resulting in lower maintenance costs. There is. In addition, since the device according to the present invention is energized during the latter half of the late-night power supply time period, if it is used in combination with conventional late-night power usage equipment whose load is concentrated in the first half, the power load peak in the first half of the power supply time period will be reduced. This also has the effect of improving power transmission efficiency.

[Brief explanation of the drawing]

Fig. 1 is a main power supply circuit diagram of a conventional hot water storage type water heater, Fig. 2 is a structural sectional view of a hot water storage type electric water heater showing an embodiment of the present invention, Fig. 3 is a control block diagram thereof, and Fig. 4 Figure, 5th
The figure is a temperature distribution diagram inside the hot water storage tank. 3 is a heating element, 1
1 is a hot water storage tank, 12 is a temperature detector, 16 is a circulation pump, 20 is residual water heat amount detection means, 21 is calculation means A, 22 is calculation means B 123 is a timer device. Agent Shin Kuzuno - (1 other person) Figure 1, 2t! ! j Figure 3 4 Figure 4 Page 5

Claims (1)

[Claims] a residual water heat amount detecting means for detecting the residual water heat amount in the hot water storage tank; a calculating means A for calculating the amount of heat to be heated from the heat amount detected by the remaining water heat amount detecting means; A calculation means B calculates the required energization time to the heating element from the amount of heat, and a calculation means B calculates the required energization time calculated by the calculation means B at the end time of the late-night electricity supply so that the heating element is energized during the late-night electricity supply time. A control device for a hot water storage type electric water heater, comprising a timer device for starting from the middle of the process.